Soldering iron



- Feb. 15, 1944. w. N. VANATTA- SOLDERING IRON Filed June 6, 1942 ywvswrora kl ////5 /V. and/f0 BY ATTORNEY Patented Feb-15, 1944 i F SOLDERING IRON Willis N. Vanatta, Ontario, CaliL; Clara Fay Vanatta administratrix of said Willis N. Vanatta, deceased Application June 6, 1942, Serial No. 446,011

3 Claims. (Cl. 219-25) This invention relates to an electrically heated soldering iron, and more particularly of the type shown in Patent No. 2,260,647, issued to Willis N. Vanatta on October 28, 1941.

Such irons are so arranged that the heating element, disposed around the copper core, or other material, can very quickly heat the core to the required temperature effective to perform the soldering operation. It is therefore important to control the heating element as by a thermostat so as to interrupt the heating element circuit whenever the temperature reaches a maximum, and to re-establish thecircuit when the temperature is lowered to a minimum.

The thermostat is mounted in good heat transfer relationship with respect to the core; for example, this can be done by supporting the thermostat structure on a projection formed on the core.

It is one of the objects of this invention to ensure that the thermostat structure will continue to function properly and will perform its cycles of controlling the heating element, repeatedly to open and close the heating circuit at the same maximum and minimum temperatures respectively. By the aid of this invention, the thermostat contacts open always at substantially the same high temperature and close always at substantially the same low temperatures. There is no marked deterioration of the thermostat even after extended use of the iron.

Due to the cyclic contraction and expansion of the core when subjected to the variations in temperature, the core parts grow, and furthermore, scale forms on the surfaces. sirable features affect the operation of the bimetallic thermostat, and cause erratic control of the heating circuit; and this erratic behavior would often causev the heating element to be burnt out.

It is another object of this invention to obviate in detail, illustrating the general principles of the invention; but it is to be understood that These unde- Figure 1 is an elevation, partly in section, of a soldering iron incorporating the invention;

to an increase in temperature.

this detailed description is not to be taken in 9.

CI r) Fig. Zis a vertical transverse section on an enlarged scale, taken along plane 2-2 of Fig. l; and

Fig. 3 is a cross section on an enlarged scale,

- taken along plane 3-3 of F18. l.

. The soldering iron includes the core 8, provided with a detachable tip 9 and the heating unit It. This heating unit or element may be in the form of a coil disposed around the core 8. The conductor forming the coil I0 is of appropriate resistance material such as nichrome, and insulated so as to withstand the temperatures attained at the core 8. This heating coil I0 is of relatively large capacity, so as to make it possible to heat the iron quite rapidly.

The core 8 has an extension ll, shown in this instance as formed integrally with the core. This extension I l serves as a supporting means for a thermostatically operated circuit controlling device for coil in. The extension II, as shown most clearly in Figs. 2 and 3 is placed slightly oil center with respect to the core 8, in order better to adapt it to support the elements of the circuit controller or switch I 2.

The switch I! includes the arms l3 and M. respectively carrying cooperating contacts i5 and ii. In the present instance contact arm [3 is formed as a fiat strip of spring material so as to render it resilient. The other arm I4 is formed of rigid material. The contacts l5 and it are urged into enragem'ent by the resilience of arm l3, ("aerating against the rigidity of arm i4. Engagement of the contact buttons l5 and I6 causes, energization of the coil ID, if the soldering iron be connected to an appropriate outlet. 1

Upon attainment of a definite high temperature by the core 8, the contact points i5 and it are caused to separate. This is accomplished for example by a bimetallic member H, which flexes toward the right as viewed in Fig. 2 in response In Fig. 2, the bimetallic member I! is shown in the position it assumes when the soldering iron is cool.

The bimetallic member I! and the arm l3 are disposed adjacent respectively opposite sides of the rigid arm I! and are properly insulated therefrom in a manner to be hereinafter described.

When member I! flexes toward the right, as viewed in Fig. 2, in response to a rise in temperature, it operates the resilient arm i3, urging it toward the right and separating contacts l5 and it. For this purpose, member is provided with an adjustable abutment 28. The abutment is in the form of aheadless screw engaging a threaded aperture in the member 97. It may be adjusted to open the contacts is and it at a predetermined higlr temperature, by threading it in or out of the threaded aperture.

' The end of the member il isslotted across the threaded aperture; the halves of the member 57, thus formed by the slot, may be pinched toward each other to clamp the screw 28 resiliently. In this way, a resilient lock for the headless screw 28 is provided, so that adjustment of the screw may be maintained securely against accidental disturbance.

The end of screw 28 is arranged, upon predetermined flexure of member it, to engage a suitable pad 29 supported on arm i3. This pad may conveniently consist of a small rivet passing through the arm and insulated from it by insulating washers 30.

The switch 02, comprising arms it and it,

I and the bimetallic member i'i, with their associated parts, is mounted on one side of the extension H. The assembly is so arranged that the bimetallic member ii is in direct heat trans-= fer relation to the extension ii; and the eie ments it, it and it? are spaced quite closely together.

Thus the rigid arm id is insulated from the spring arm why the aid of insulation 23, such as mica, interposed between the lower ends of these arms; similarly insulation material 22, such as mica, is interposed between arm i i and the member 9?. The insulation 22 is substantially coextensive with the bimetallic element ll, thereby effectively preventing it from com ing into contact with the arm i i. Apertures 32 and G! are provided near the upper ends of arm id and the upper end of insulation material 22 to leave a clear passage for abutment 28 in its movement toward the pad 29. The er.- tent of fiexure of member 57 to open the con tacts i5 and i6 is affected by the spacing of the lower ends of member i7 and arm i3. This spacing is represented by the thickness of in- All of the insulated members described are capable of withstanding the high temperatures encountered during operation of the soldering iron.

The terminals for coil l9 may be appropriately connected to the switch i2 and to the source of supply; for example, one terminal 38 (Fig. 2) is connected to contact arm i3, as by being clamped against nut 21 on screw 24 by I another nut 31. The other terminal 38 passes into the handle structure and is'there connected to one conductor of the supply cord 39. The other conductor of the supply cord is connected by lead 58 attached to the projection 33 of arm it, by a screw ii. The complete circuit for the coil thus extends through lead 38, coil i0, lead 36, nut 27, screw 25, arm l3, contacts i5 and i6, arm' id, projection 33, and lead 436.

Due to the intimate thermal contact between bimetallic member ill and extension ii this bimetallic metal it responds promptly to temperature variations of core 8. As the core temperature increases the member ll flexes toward the right. Upon attainment of a definite high temperature the abutment 28 urges pad 29 toward the right to flex arm 53 out of contacting relationship. When the iron cools sufiiciently the member i? flexes toward the left, and after a time the circuit is re-established by withdrawal of the abutment 28 from the pad 29.

The tip 9 (Fig. 1) is detachably secured to the bottom of core 8 by a threaded extension 55. This extension engages a correspondingly threaded opening dd in core 8. It is the intention to have tips of different sizes and coniigurations to suit the character of the work. A hexagonal flange ll' may be provided for the tip 9 to facilitate removal and replacement in the core 8.

Coil it and switch 52 are enclosed ina metal tube or sheath-Eii.\ This sheath may have an inwardly directed flange 51 on its lower end through which the threaded portion 65 of the tip 8 may pass. The upper end of the sheath 56 is secured to a cap member 52 which in turniis secured to a small diameter tube 53. This tube 53 carries aiiange 5d at its upper end.\ A wood handle 55 is attached to the flange 5%.\F0r this purpose, the .fiange 5d rests in the counterbore 56 in the ad bottom of the handle. \A pair of long screws 5! to disturb the regularity of the cycles of fiexme of the member ii. Accordingly the switch 12 can-be relied upon to operate at the required limiting temperatures. The coil iii is assured against being burned out.

In order to hold the parts in assemblechrelatlon on one side of extension ii,-use is made of a screw or bolt it. This bolt passes through the, aperture 2%, lined with an insulating bushing 21]. This insulating bushing extends toward the right of the projection H, as viewed in Fig. 2. It passes through appropriate apertures in the bimetallic member it, insulation 22, and arm i l, and abuts against the insulation material 23, which may also be of mica.

In order to insulate projection ii completely, an insulation washer 25 of mica or the like is disposed on the left hand side of the projection H. A metal washer 25 may be disposed between the insulation washer 2t and the head of bolt 2Q.

A nut 27 is threaded over the right hand and of the bolt 26 to hold the parts in the assembly relation shown in Fig. 2.

serve to attach the handle to the flange 54.

In order to prevent the transmission of any material tension from cord 35 upon the leads for the coil iii, a terminal board 66 of insulation material is provided in the'handle. This board so is of relatively thin material having a length substantially equal\ to that of the s ace in the handle\55, defined flange 56 and he upper y b collar as It is also grovided with slots 62 at its opposite ends. The bonductors 38 and 0 are permitted by the lower: slot to pass on opposite sides of the board 60, and. to terminate at terminals 5b and 5e supported b the board. The twin conductors of cord 3%? are respeqtively attached to these terminals. The board alsb. has a pair of apert s 63 through which cord 39 is threaded. Thus a pull on cbrdiijS cannot be transmitted beyond the boardtll} because' of the 1iriction encountered at ah edges of these aperures.

1 What is claimed is:

asere 7 stationary arm, a contact supported by the arm, a flexible arm, a contact co-operating with the stationary contact and supported by the flexible arm, a bi-metallic member, means insulating said arms from one another and. from the core and its extension, means for transmitting motion from the bimetallic member to the flexible arm and electrically insulated from at least one of the arms, and means for attaching the two arms and the bimetallic member to one side of the core projection, and with the bimetallic member in intimate heat exchanging contact with said pro- Jection.

2. In an electrically heated soldering iron, a core having an extension, an electric heating element surrounding the core, and-a thermostatic switch for controlling said circuit, comprising a first arm, a contact supported by the arm, a second arm made from resilient material, a contact cooperating with the contact supported by the first arm, and supported on said second arm, insulation material between one side of the first arm, and the second arm, a flexible bimetallic arm and the said bimetallic member, and fastening means passing through the arms and the bi .metallic member, and engaging said extension.

3. In an electrically heated soldering iron, a core having anextension, an electric heating ele-- ment surrounding the core, and a thermostatic switch for controlling said circuit, comprising a first arin, a contact supported by the arnna second arm made from resilient material, a contact cooperating with the contact supported by the first arm, and supported on said second arm, insulation material between one side of the first arm, and the second arm, a flexible bimetallic member disposed on the other side of said first arm and in intimate contact with said extension, said bimetallic member operating to move said second arm, insulation material between the first arm and the said bimetallic member, said first arm and the insulation material between said first arm and the bimetallic member having apertures to permit said bimetallic member to operate said second arm, said contact remaining in engagement during a portion of the flexing of member disposed on the other side of said first arm and in intimate contact with said extension, said bimetallic member operating to move said second arm, insulation material between the first the bimetallic member, and fastening means passing through the arms and the bimetallic member, and engaging said extension.

WILLIS N. VAPIATTA. 

